JP3148109B2 - Method for forming the insertion protrusion of cast iron pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a ring-shaped insertion projection for preventing the connection from coming off at the outer periphery of the front end of the insertion at the connection of a cast iron pipe.

[0002]

2. Description of the Related Art As shown in FIG. 2, a stopper ring 3 'made of a tough cast iron such as steel or ductile cast iron is generally fixed to a connection portion of a cast iron tube 1, particularly an outer peripheral surface 2a of an insertion opening 2. By doing so, an annular insertion projection 3 is formed. A groove 5 is formed on the inner peripheral surface of the receiving port 4 on the mating side of the connection side of the cast iron tube 1, and a lock ring 6 having a circumferentially split shape is formed in the groove 5 via a centering rubber ring 7. The lock ring 6 and the insertion projection 3 are engaged with each other, so that the connection portions of the cast iron pipe 1 are not separated from each other. Reference numeral 8 in FIG. 2 denotes a rubber ring disposed between the groove 9 near the opening end of the receiving port 4 and the outer peripheral surface 2a of the insertion port 2.

Conventionally, the stopper ring 3 'is integrally fixed to the insertion port 2 of the cast iron pipe 1 as described below to form the insertion projection 3. As shown in FIG. 3A, the stopper ring 3 'forming the insertion projection 3 has a tight fit whose inner diameter D1 is slightly smaller than the outer diameter D2 of the cast iron tube 1 in a state where no external force is applied. Like that. The stopper ring 3 ′ is disposed in such a position that the groove 3 b is formed at a position near the front end of the insertion opening on the inner peripheral surface 3 a of the stopper ring 3 ′, and a wire 11 made of brazing material is provided in the groove 3 b.
Is inserted. Then, the inner peripheral surface 3a of the stopper ring 3 'and the stopper ring 3'
And a flux (not shown) for a brazing filler metal is applied in advance to a portion where the bonding is performed.

Next, as shown in FIG. 3 (b), the stopper ring 3 'on which the wire 11 is disposed is connected to one end 3c which is disposed on the distal end side of the stopper ring 3'. By pressing it toward the side, it is externally fitted in the insertion opening outer peripheral surface 2a in a press-fit state.

After that, the cast iron pipe 1 is heated from the inner peripheral side of the pipe to melt the wire 11 in the groove 3b of the stopper ring 3 '. Thereby, as shown in FIG. 3C, the stopper ring 3 ′ and the insertion port 2 of the cast iron pipe 1 are joined by the brazing material 11 ′ to form the insertion projection 3 on the outer periphery of the insertion port 2. .

Finally, as shown in FIG. 3 (d), the outer peripheral surface of the front end of the insertion port 2 and the front end portion of the insertion projection 3 are again tapered so that the front end becomes thinner. Surface 12 is formed. Here, when performing this taper processing, a portion including the groove 3b of the stopper ring 3 'is scraped off, and finally the stopper ring 3' and the insertion opening 2 are joined without the groove 3b. An insertion projection 3 is formed.

According to this method, since the groove 3b is formed in the inner peripheral surface 3a of the stopper ring 3 'and the wire 11 made of brazing material is disposed in the groove 3b, a sufficient amount of the wire 11 is provided. Wire 11
Is melted and the brazing material 11 ′ spreads well between the stopper ring 3 ′ and the outer peripheral surface 2 a of the insertion opening 2. Further, as shown in FIG. 3 (d), the joint between the stopper ring 3 'and the insertion opening 2 of the cast iron tube 1 is finally joined without the groove 3b of the stopper ring 3'. Therefore, a sufficient joining area between the insertion projection 3 and the insertion port 2 of the cast iron pipe 1 can be secured, and a sufficient joining force can be obtained.

[0008] Thereafter, the rubber ring 8, the centering rubber ring 7, and the lock ring 6 are inserted into the insertion port 4 provided in advance.
At this time, the rubber ring 8 and the lock ring 6 are guided by the tapered surface 12 of the insertion opening 2 to expand the diameter, and the insertion of the insertion opening 2 into the receiving opening 4 is allowed.

[0009]

However, in the above-mentioned conventional method for forming the insertion projection, as shown in FIG. 4, one end 3c of the stopper ring 3 'is pressed toward the back of the insertion port. When the stopper ring 3 ′ is externally fitted to the outer peripheral surface 2 a of the insertion port by press-fitting, the groove 3 b expands together with the other end 3 d of the stopper ring 3 ′, and the groove 3 b of the stopper ring 3 ′. The wire 11 may fall off from the wire.

The present invention solves the above-mentioned problems, and a method for forming an insertion projection of a cast iron pipe in which a brazing material such as a wire does not fall off from a groove of a stopper ring while a sufficient joining force can be obtained. The purpose is to provide.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problem, the present invention is to form a groove on the inner peripheral surface of a stopper ring which finally becomes an insertion projection of a cast iron pipe, and to form a groove in the groove of the stopper ring. A brazing material is disposed, and a stopper ring on which the brazing material is disposed is pressed at one end of the stopper ring at the front end side of the insertion port toward the back side of the insertion port, so that a connection portion of the cast iron pipe is formed. Press-fit onto the outer peripheral surface of the insertion hole at
A cast iron tube that forms a spigot for preventing a connection part from being detached by heating a portion including a brazing material disposing portion and melting the brazing material, thereby brazing and joining a stopper ring and an opening of the cast iron tube. Forming the groove of the stopper ring at a position near the front end of the stopper ring on the inner peripheral surface of the stopper ring before fitting the stopper ring to the stopper hole. The outer periphery of the portion arranged on the distal end side is tapered to a position near the groove portion, the thickness of the stopper ring from this tapered surface to the groove portion is reduced to form a thin portion, and inserted from one end of the stopper ring. The stopper ring is bent at the thin portion by the pressing force pressed toward the back side of the mouth, and one end side of the stopper ring is deformed inward.

According to the above method, when the stopper ring is pressed toward the inner side of the insertion hole and press-fitted, the stopper ring is bent at the thin portion and one end of the stopper ring is deformed inward. The opening side of the groove is narrowed, so that the brazing material is securely held in the groove of the stopper ring, and the brazing material is prevented from dropping out of the groove of the stopper ring.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. The components having the same functions as those of the related art are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 1A, the inner diameter D1 of the stopper ring 3 'forming the insertion projection 3 is slightly smaller than the outer diameter D2 of the cast iron pipe 1 when no external force is applied. It is configured to be fitted. The stopper ring 3 ′ is arranged in such a manner that the groove 3 b is formed at a position near the leading end of the insertion opening on the inner peripheral surface of the stopper ring 3 ′, and the wire 11 made of brazing material is fitted into the groove 3 b. .

Further, the outer periphery of a portion of the stopper ring 3 'located on the leading end side of the insertion opening is tapered to a position near the groove 3b, and the thickness of the stopper ring 3' from the tapered surface 3d to the groove 3b is reduced. Thus, a thin portion 3e is formed.

Therefore, as shown in FIG.
When the stopper ring 3 ′ is pressed (indicated by an arrow) on the one end 3 c disposed on the distal end side of the insertion port of the stopper ring 3 ′ toward the inner side of the insertion port so as to externally fit the outer peripheral surface 2 a of the insertion port 2, Since the pressing point is closer to the inner periphery than the thin portion 3e of the stopper ring 3 ', the one end 3c side of the stopper ring 3' is deformed inward with the thin portion 3e of the stopper ring 3 'as a bending point. Thereby, the groove 3 of the stopper ring 3 '
Since the opening side of b is narrowed, the wire 11 is securely held in the groove 3b of the stopper ring 3 ', and is prevented from dropping out of the groove 3b of the stopper ring 3'.

Further, the stopper ring 3 ′ is inserted into the insertion port 2.
1 (c), the one end 3c of the stopper ring 3 'comes into close contact with the outer peripheral surface of the insertion port 2 while returning to the unbent state before deformation, as shown in FIG.

Thereafter, as in the prior art, the cast iron pipe 1 is heated from the inner peripheral side of the pipe to melt the wire 11 in the groove 3b of the stopper ring 3 ', thereby, as shown in FIG. As described above, the stopper ring 3 ′ and the insertion port 2 of the cast iron pipe 1 are joined by the brazing material 11 ′, and the insertion projection 3 is provided on the outer periphery of the insertion port 2.

Finally, as shown in FIG. 1E, the outer peripheral surface of the front end of the insertion port 2 and the front end portion of the insertion projection 3 are again tapered so that the front end becomes thinner. Surface 12 is formed. Here, when the taper processing is performed, the portion including the groove 3b of the stopper ring 3 'and the aforementioned tapered surface 3d of the stopper ring 3'
And the stopper projection 3 is formed in a state where the stopper ring 3 ′ and the stopper 2 are finally joined without the groove 3b.

Here, in the conventional method of forming an insertion projection, when the stopper ring 3 'is externally fitted to the insertion outer peripheral surface 2a in a press-fit state, the groove 3b is formed together with the other end 3d of the stopper ring 3'. Has spread, and the stopper ring 3 '
The wire 11 may fall off from the groove 3b of
However, as described above, in this insertion projection forming method, when the stopper ring 3 ′ is externally fitted to the insertion outer peripheral surface 2 a in a press-fit state, the stopper ring 3 ′ is formed.
The stopper ring 3 'is bent at the thin portion 3e by the pressing force pressed from the one end 3c of the wire 11 toward the rear side of the insertion opening, and the opening side of the groove 3b is narrowed.
Does not drop out of the groove 3b of the stopper ring 3 'at all.

It goes without saying that the size of the cast iron tube 1 and the stopper ring 3 'and the type of the brazing material 10 are not limited to those described above.

[0022]

As described above, according to the method for forming an insertion projection of a cast iron pipe of the present invention, before the stopper ring is fitted to the insertion port, the groove of the stopper ring is formed on the inner peripheral surface of the stopper ring. The stopper ring is formed at a position close to the front end of the opening and the outer periphery of a portion arranged on the front end side of the stopper ring is tapered to a position near the groove to reduce the thickness of the stopper ring from the tapered surface to the groove. By forming a thin portion and pressing the stopper ring from the one end of the stopper ring toward the back of the insertion port, the stopper ring is bent at the thin portion to deform the one end of the stopper ring inward. Since the opening side of the groove portion of the stopper ring is narrowed, the brazing material is securely held in the groove portion of the stopper ring, and the brazing material is prevented from dropping out of the groove portion of the stopper ring.

[Brief description of the drawings]

FIGS. 1A to 1E are cross-sectional views showing respective steps in a method for forming an insertion projection of a cast iron pipe according to an embodiment of the present invention.

FIG. 2 is a sectional view of a joint portion of a cast iron pipe.

3 (a) to 3 (d) are cross-sectional views showing respective steps in a conventional method for forming an insertion projection of a cast iron pipe.

FIG. 4 is a cross-sectional view showing a step of fitting a stopper ring to an insertion hole in a conventional method for forming an insertion protrusion of a cast iron pipe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cast iron pipe 2 Insertion opening 2a Outer peripheral surface 3 Inserting projection 3 'Stopper ring 3a Inner peripheral surface 3b Groove 3c One end 3d Tapered surface 3e Thin portion 11 Wire 11' Brazing material

Continuation of the front page (56) References JP-A-7-155937 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16L 21/00-21/08 B23K 1/18

Claims (1)

(57) [Claims] A groove is formed in an inner peripheral surface of a stopper ring which finally becomes an insertion projection of a cast iron pipe, a brazing material is provided in the groove of the stopper ring, and a stopper provided with the brazing material is provided. By pressing one end portion of the stopper ring, which is located at the front end side of the insertion port, toward the back side of the insertion port, the ring is fitted to the outer peripheral surface of the insertion port at the connection portion of the cast iron pipe in a press-fit state, and the brazing material is used. By heating the portion including the disposition portion to melt the brazing material, the stopper ring and the insertion opening of the cast iron tube are brazed and joined to form an insertion projection for preventing the connection portion from being detached. In a method of forming a mouth projection, a groove portion of a stopper ring is formed at a position on an inner peripheral surface of the stopper ring near a tip end of the stopper ring before the stopper ring is externally fitted to the mouth of the stopper ring. In front of the perimeter of The stopper ring from this tapered surface to the groove is tapered to a location near the groove to form a thinner portion, and a pusher is pressed from one end of the stopper ring toward the back of the insertion opening. By pressure,
The stopper ring is bent at the thin portion to deform one end side of the stopper ring inward, thereby narrowing the opening side of the groove portion of the stopper ring and holding the brazing material in the groove portion of the stopper ring. A method for forming an insertion projection of a cast iron tube.